Re-Fracturing Technology Research and Application for Low Permeability Reservoirs in Huabei Oilfield

Abstract

The research on the mechanism of repeated fracturing fractures shows that the pressure drop caused by the initial fracturing fractures and the production activities of the oil layer in the repeated fracturing wells leads to changes in the stress field near the well, which causes the fractures to re-fract during the repeated fracturing process. Combining with the low permeability characteristics of Tongxi fault block reservoir in North China Oilfield, optimization of repeated fracturing parameters and selection of fracturing materials were carried out, and the principle of well selection and layer selection was put forward. The repeated fracturing technology was successfully implemented in the Tong47-43x well and achieved a good oil-increasing effect, which provided important technical measures for the next development of the Tongxi fault block reservoir.

Preparation of Low-Viscosity Epoxy Resin Sealing Agent and Evaluation of Injection, Plugging, and Degradation Properties

“…The technology of water plugging and increasing production in high water cut reservoirs of low permeability is a common problem in the industry. , To enormously increase reservoir production, the composite technology of water plugging and fracturing by plugging first water breakthrough reservoirs and then fracturing new fractures was proposed, which is beneficial to long-term stable production. However, with the continuous advancement of field execution, it was believed that the plugging agent was critical, and its comprehensive performance plays a crucial role in the application process . Nowadays, the commonly used plugging materials, such as inorganic gels, organic gels, and cement, for external sealing of horizontal well casing channeling, casing damage repair of oil and gas wells, and sealing the high moisture content well during the construction of the repeated fracturing had the following problems: − (1) The conventional plugging agent was diluted easily by oil or formation water to induce the ineffectiveness of water plugging.…”

“…However, with the continuous advancement of field execution, it was believed that the plugging agent was critical, and its comprehensive performance plays a crucial role in the application process. 12 Nowadays, the commonly used plugging materials, such as inorganic gels, organic gels, and cement, for external sealing of horizontal well casing channeling, casing damage repair of oil and gas wells, and sealing the high moisture content well during the construction of the repeated fracturing had the following problems: 13 − 16 (1) The conventional plugging agent was diluted easily by oil or formation water to induce the ineffectiveness of water plugging. (2) The driven water readily broke through the sealing zone for the low adhesion strength agent and the surface layer of casing pipes, cement sheaths, and rocks.…”

Experimental Investigation on the Stability of Oil-Based Nitrogen Foam under Ultrahigh Pressure and Elevated Temperature

“…With the increasing demand for energy and the deepening of oilfield development, the available reserves of conventional reservoirs are decreasing. − The effective development of unconventional oil resources, such as low-permeability and tight reservoirs, is playing an increasingly important role in energy supply. − To realize industrial production, low-permeability and tight reservoirs are usually fractured at first to improve permeability, followed by water flooding or gas flooding. − Low-permeability and tight reservoirs are characterized by low permeability, poor reservoir flow capacity, a large difference in plane physical properties, and a rapid decline in formation energy. − Therefore, it is difficult to maintain the water injection pressure, and the oil recovery of water flooding is low . For these two types of reservoirs, gas flooding offers unique advantages over other production practices .…”